/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;

import java.util.Collection;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.CheckForNull;

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A multimap which forwards all its method calls to another multimap. Subclasses should override
 * one or more methods to modify the behavior of the backing multimap as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMultimap}.
 *
 * @author Robert Konigsberg
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ForwardingMultimap<K extends @Nullable Object, V extends @Nullable Object>
        extends ForwardingObject implements Multimap<K, V>
{

    /**
     * Constructor for use by subclasses.
     */
    protected ForwardingMultimap()
    {
    }

    @Override
    protected abstract Multimap<K, V> delegate();

    @Override
    public Map<K, Collection<V>> asMap()
    {
        return delegate().asMap();
    }

    @Override
    public void clear()
    {
        delegate().clear();
    }

    @Override
    public boolean containsEntry(@CheckForNull Object key, @CheckForNull Object value)
    {
        return delegate().containsEntry(key, value);
    }

    @Override
    public boolean containsKey(@CheckForNull Object key)
    {
        return delegate().containsKey(key);
    }

    @Override
    public boolean containsValue(@CheckForNull Object value)
    {
        return delegate().containsValue(value);
    }

    @Override
    public Collection<Entry<K, V>> entries()
    {
        return delegate().entries();
    }

    @Override
    public Collection<V> get(@ParametricNullness K key)
    {
        return delegate().get(key);
    }

    @Override
    public boolean isEmpty()
    {
        return delegate().isEmpty();
    }

    @Override
    public Multiset<K> keys()
    {
        return delegate().keys();
    }

    @Override
    public Set<K> keySet()
    {
        return delegate().keySet();
    }

    @CanIgnoreReturnValue
    @Override
    public boolean put(@ParametricNullness K key, @ParametricNullness V value)
    {
        return delegate().put(key, value);
    }

    @CanIgnoreReturnValue
    @Override
    public boolean putAll(@ParametricNullness K key, Iterable<? extends V> values)
    {
        return delegate().putAll(key, values);
    }

    @CanIgnoreReturnValue
    @Override
    public boolean putAll(Multimap<? extends K, ? extends V> multimap)
    {
        return delegate().putAll(multimap);
    }

    @CanIgnoreReturnValue
    @Override
    public boolean remove(@CheckForNull Object key, @CheckForNull Object value)
    {
        return delegate().remove(key, value);
    }

    @CanIgnoreReturnValue
    @Override
    public Collection<V> removeAll(@CheckForNull Object key)
    {
        return delegate().removeAll(key);
    }

    @CanIgnoreReturnValue
    @Override
    public Collection<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values)
    {
        return delegate().replaceValues(key, values);
    }

    @Override
    public int size()
    {
        return delegate().size();
    }

    @Override
    public Collection<V> values()
    {
        return delegate().values();
    }

    @Override
    public boolean equals(@CheckForNull Object object)
    {
        return object == this || delegate().equals(object);
    }

    @Override
    public int hashCode()
    {
        return delegate().hashCode();
    }
}
